There has been studied a high speed position data searching service which gathers and manages position data including latitudes and longitudes of, for example, mobile entities and facilities. One example of the content of the search service, there is a search for a group of mobile entities included in a certain range (e.g., facility).
Patent Document 1: Japanese Laid-Open Patent Publication No. 2007-41189
The use of RDB (Relational Database) is one way of managing position data of, for example, mobile entities or facilities. For example, IDs and position data of the mobile entities or facilities may be registered to the RDB as attributes as of the mobile entities and facilities.
However, in a case of, for example, searching a group of mobile entities included in a certain range, it becomes necessary to compare the certain range and the position data of all of the records. The mobile entities, which are the targets to be managed, not only include vehicles on which vehicle devices are mounted but also include, for example, people carrying mobile terminals. Therefore, the number of records could be several tens of millions or more. Thus, it is difficult to attain a practical searching performance by comparing the position data of all of the records with the certain range.
In order to improve searching performance, there is a method of forming indices pertaining to position data. However, in this case, the indices are to be rearranged frequently because position data of the mobile entities continue to change constantly. Thus, the workload for the rearranging becomes a significantly large.
In addition, technically, the mobile entities are not positioned as points but are positioned as expansions. For example, in a case of managing position data of mobile entities such as typhoons or nimbuses, it is significant to manage their positions and their range. However, in order to search for mobile entities included in a certain range or for mobile terminals overlapping the certain range, it becomes necessary to calculate, for example, an inclusion relationship between the certain range and the ranges of the mobile entities. Thereby, search performance may be further degraded.